TOPSHOTS
A helicopter lifts a person off the roof as police respond to the report of a shooting at the Navy Yard in Washington, Dc on September 16, 2013. Departures have been halted at Washington's Reagan National Airport due to a shooting at the US Navy Yard, an official said Monday. Chris Paolino, a spokesman for the airport, said inbound aircraft are still landing and that the airport remains open to passengers. "We can confirm that the FAA (Federal Aviation Administration) has halted aircraft departures from Reagan National due to an active law enforcement incident at the Washington Navy Yard," Paolino told AFP via email. Several people have been wounded in the shooting at the nearby US Navy Yard in Washington, authorities said. The Navy said at least three shots were fired at 8:20 am (1320 GMT) in the headquarters building of the Naval Sea Systems Command. AFP PHOTO / Saul LOEBSAUL LOEB/AFP/Getty Images
Photo: Saul Loeb, AFP/Getty Images

TOPSHOTS
A helicopter lifts a person off the roof as police...

US President Barack Obama arrives to speak on economy in the South Court Auditorium of the Eisenhower Executive Office Building, next to the White House, in Washington, DC, on September 16, 2013 to mark the five-year anniversary of the financial crisis. Obama on Monday condemned the "cowardly" shooting at the Washington Navy Yard, and vowed a "seamless" operation to administer justice to those responsible. One gunman was killed and two other potential shooters remain at large, police said, after the attack in the naval installation, just a few miles across Washington from the White House. AFP Photo/Jewel SamadJEWEL SAMAD/AFP/Getty Images
Photo: Jewel Samad, AFP/Getty Images

US President Barack Obama arrives to speak on economy in the South...

A man and woman embrace while reuniting at a gathering point for family members of Navy Yard employees that was set up inside Nationals Park in the wake of the shooting September 16, 2013 in Washington, DC. Police believe at least one gunman shot and killed at least 12 people and wounded others in an incident that put parts of the city on lockdown.
Photo: Win McNamee, Getty Images

A man and woman embrace while reuniting at a gathering point for...

This booking photo provided by the Fort Worth Police Department shows Aaron Alexis, arrested in September, 2010, on suspicion of discharging a firearm in the city limits. The FBI has identified Alexis, 34, as the gunman in the Monday, Sept. 16, 2013 shooting rampage at at the Washington Navy Yard in Washington that left thirteen dead, including himself.
Photo: Fort Worth Police Department

This booking photo provided by the Fort Worth Police Department...

Police respond to the report of a shooting at the Navy Yard in Washington, DC, September 16, 2013. At least one unidentified gunman opened fire at the US Navy Yard in Washington on Monday and was at large after killing "multiple" victims and wounding several more, officials said. Police and FBI agents descended on the area in force as helicopters swarmed overhead, amid reports a shooter was armed with an assault rifle and was holed up at the complex. "We believe there were multiple deaths," a US defense official, speaking on condition of anonymity, told AFP. The precise death toll remained unclear, the official said. A Washington DC police officer and another law enforcement officer had been shot while the gunman had allegedly barricaded himself in a room in a headquarters building, media reported.
Photo: SAUL LOEB, AFP/Getty Images

Police respond to the report of a shooting at the Navy Yard in...

A DC Police patrol boat speeds down the Anocostia River next to the US Navy yard September 16, 2013 in Washington, DC. At least one unidentified gunman opened fire at the US Navy Yard in Washington on Monday and was at large after killing "multiple" victims and wounding several more, officials said. Police and FBI agents descended on the area in force as helicopters swarmed overhead, amid reports a shooter was armed with an assault rifle and was holed up at the complex. "We believe there were multiple deaths," a US defense official, speaking on condition of anonymity, told AFP. The precise death toll remained unclear, the official said. A Washington DC police officer and another law enforcement officer had been shot while the gunman had allegedly barricaded himself in a room in a headquarters building, media reported.
Photo: PAUL J. RICHARDS, AFP/Getty Images

A DC Police patrol boat speeds down the Anocostia River next to the...

A flag at the U.S. Capitol has been lowered to half staff to honor the victims of today's shooting at the Washington Navy Yard, September 16, 2013 in Washington, DC. The U.S. Senate was in lock down and security has been tightened due to today's mass shooting at the Washington Navy Yard where at least 12 people were shot and killed by a gunman.
Photo: Mark Wilson, Getty Images

A flag at the U.S. Capitol has been lowered to half staff to honor...

People hold their hands to their heads as they are escorted out of the building where a gunman was reported at the Washington Navy Yard in Washington, Monday, Sept. 16, 2013. At least one gunman opened fire inside a building at the Washington Navy Yard on Monday morning.
Photo: Jacquelyn Martin, Associated Press

People hold their hands to their heads as they are escorted out of...

Dr. Janis M. Orlowski, chief operating officer at Washington Hospital Center speaks at a news conference in Washington, Monday, Sept. 16, 2013, about the conditions of the people who were brought to the hospital from the shooting at the Washington Navy Yard building. Orlowski said the hospital was treating three gunshot victims in critical condition. One was Washington, D.C., metropolitan police officer and two were civilian women.
Photo: Jose Luis Magana, AP

Dr. Janis M. Orlowski, chief operating officer at Washington...

Police respond to the report of a shooting at the Navy Yard in Washington, DC, September 16, 2013. A gunman shot and wounded at least one person Monday in a headquarters building at the US Navy Yard in Washington and is still at large, the navy said."There is one confirmed injury. Emergency personnel are on scene and a 'shelter in place' order has been issued for Navy Yard personnel," the navy said in a statement. Local television reported that there were as many as five casualties and the Navy said that police had entered building number 197 in search of the shooter. The Navy said at least three shots were fired at 8:20 am (1320 GMT) in the headquarters building of the Naval Sea Systems Command.
Photo: SAUL LOEB, AFP/Getty Images

Police respond to the report of a shooting at the Navy Yard in...

A man walks with a woman after they were reunited at a family gather point for Navy Yard shootings set up at parking lot B of Nationals Park on September 16, 2013 in Washington, DC.
Photo: MANDEL NGAN, AFP/Getty Images

A man walks with a woman after they were reunited at a family...

Staff of the Naval Sea Systems Command headquarters exchange a salute while being greeted by family and friends as they are bused from the Washington Navy Yard to Nationals Park, in Washington, Monday, Sept. 16, 2013. At least one gunman launched an attack inside the Washington Navy Yard, spraying gunfire on office workers in the cafeteria and in the hallways at the heavily secured military installation in the heart of the nation's capital, authorities said.
Photo: Jacquelyn Martin, ASSOCIATED PRESS

Staff of the Naval Sea Systems Command headquarters exchange a...

Paul Mills of Silver Spring, MD, and Nichole Goble of Washington, D.C. hold candles to remember victims of gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Paul Mills of Silver Spring, MD, and Nichole Goble of Washington,...

A man and woman embrace while reuniting at a gathering point for family members of Navy Yard employees that was set up inside Nationals Park in the wake of the shooting September 16, 2013 in Washington, DC. Police believe at least one gunman shot and killed at least 12 people and wounded others in an incident that put parts of the city on lockdown.
Photo: Win McNamee, Getty Images

A man and woman embrace while reuniting at a gathering point for...

A police officer runs along M Street Southeast, near 6th Street during a shooting at the Washington Navy Yard on September 16, 2013 in Washington, DC.
Photo: The Washington Post, The Washington Post/Getty Images

A police officer runs along M Street Southeast, near 6th Street...

People run to take shelter on Pennsylvania Avenue after reports of the sounds of shots in front of the White House September 16, 2013 in Washington, DC. A man was tackled after allegedly throwing lit firecrackers over the White House fence, according to published reports. A gunman killed 12 people at the Washington Navy Yard today, according to recent published reports.
Photo: Pool, Getty Images

People run to take shelter on Pennsylvania Avenue after reports of...

A police boat and helicopter patrol near the scene of a shooting at the Washington Navy Yard on Monday, Sept. 16, 2013, in Washington. At least one gunman opened fire inside a building at the Washington Navy Yard, and officials said six people were killed and as many as 10 were wounded, including a law enforcement officer.
Photo: Evan Vucci, ASSOCIATED PRESS

A police boat and helicopter patrol near the scene of a shooting at...

A reporter knocks on the door of the last known address of Aaron Alexis Monday, Sept. 16, 2013, in Fort Worth, Texas. Police have identified Alexis as the gunman in Monday's shooting rampage at at the Washington Navy Yard in Washington. Mayor Vincent Gray said at a news conference Monday afternoon that Alexis was among the dead.
Photo: LM Otero, Associated Press

A reporter knocks on the door of the last known address of Aaron...

Brittany Carter holds a candle in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter holds a candle in remembrance of people affected by...

Brittany Carter, of Bowie, MD., (L) and Jibri Johnson, of Landon, MD., hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) and Jibri Johnson, of Landon,...

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD., (C) and Bryan Beard of Washington D.C. hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD.,...

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD., (C) and Bryan Beard of Washington D.C. hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD.,...

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD., (C) and Bryan Beard of Washington D.C. hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD.,...

Dave Gray and wife Brittany, of Salt Lake City, hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Dave Gray and wife Brittany, of Salt Lake City, hold candles in...

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD., (C) and Bryan Beard of Washington D.C. hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD.,...

Gordon Morris (L) and wife Laura watch as the flags are lowered to half mast during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Gordon Morris (L) and wife Laura watch as the flags are lowered to...

Eddie Weingart of Project End Gun Violence speaks to members of the media during a candlelight vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which Weingart called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Eddie Weingart of Project End Gun Violence speaks to members of the...

Eddie Weingart of Project End Gun Violence speaks to members of the media during a candlelight vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which Weingart called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Eddie Weingart of Project End Gun Violence speaks to members of the...

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD., (C) and Bryan Beard of Washington D.C. hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Brittany Carter, of Bowie, MD., (L) Jibri Johnson, of Landon, MD.,...

Nichole Goble of Washington, D.C. holds a candle to remember victims of gun violence during a vigil at Freedom Plaza on September 16, 2013 in Washington, DC. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

Nichole Goble of Washington, D.C. holds a candle to remember...

Women embrace while reuniting at a gathering point for family members of Navy Yard employees that was set up inside Nationals Park in the wake of the shooting September 16, 2013 in Washington, DC. Police believe at least one gunman shot and killed at least 12 people and wounded others in an incident that put parts of the city on lockdown.
Photo: Win McNamee, Getty Images

Women embrace while reuniting at a gathering point for family...

A reporter knocks on the door of the last known address in Fort Worth of Aaron Alexis on Monday. The bungalow is behind a Buddhist temple he attended.
Photo: LM Otero, STF

A reporter knocks on the door of the last known address in Fort...

A flag at the U.S. Capitol has been lowered to half staff to honor the victims of the shooting at the Washington Navy Yard.
Photo: Mark Wilson, Getty Images

A flag at the U.S. Capitol has been lowered to half staff to honor...

Brittany Carter, of Bowie, Md., left, Jibri Johnson, of Landon, Md., and Bryan Beard, of Washington, D.C., hold candles in remembrance of people affected by gun violence during a vigil at Freedom Plaza in Washington, D.C., Monday night. The vigil, during which organizers called for stricter gun laws, was in remembrance of the 12 victims killed in a shooting at the Washington Navy Yard earlier in the day.
Photo: Greg Kahn, Getty Images

FORT WORTH — As lone gunmen involved in mass shootings go, Aaron Alexis defied the standard profile: He was black, Buddhist and reasonably sociable. Friends and acquaintances were stunned that the quiet computer network technician would show up at a federal military office Monday and open fire with not a word of warning or explanation.

But that's not to say the 34-year-old Alexis, who until recently lived for several years in suburban Fort Worth, did not have moments that hinted at a troubled personality. For starters, the New York native reportedly was discharged in 2011 from the Navy because of unspecified infractions, one of which involved a weapon discharge that sent a bullet into a neighbor's apartment.

Alexis was arrested but never charged. Police ultimately accepted his explanation that the gun went off accidentally while he was cleaning it, even though the woman who lived in the apartment above him told them she was terrified of her neighbor. She said he had repeatedly called police about her for noise-related issues and had confronted her in the parking lot.

Alexis had at least one other gun-related incident in his past. He was living in Seattle in 2004 when he was suspected of shooting out another man's tires in what police described as an anger-fueled "blackout."

Police contend he shot out the tires of a car parked near his grandmother's home in Seattle's Beacon Hill neighborhood. According to a police statement, Alexis was suspected of firing two rounds into the rear tires of a Honda Accord, then shooting once into the air before returning to the home, which was next door to the construction site where the car had been parked.

Said he was mocked

The owner of the construction business told police he believed Alexis was angry over the parking situation around the work site. Seattle detectives arrested him a month later. Alexis told detectives he had been "mocked" by construction workers and said they had "disrespected him." Alexis also claimed he had blacked out and could not remember firing his gun at the victims' vehicle until an hour after the incident.

Angry is a word that pops up periodically in conversations about Alexis. A roommate called Fort Worth police to report his suspicion that Alexis had put something into his gas tank with the purpose of damaging his vehicle. There also was a 2008 arrest in Atlanta for disorderly conduct, though details were not immediately available.

Alexis' father, Algernon Alexis, told Seattle police that his son had anger management problems. He blamed them partly on his son's active participation in rescue efforts after the 9/11 World Trade Center bombings. When reached Monday, Algernon Alexis said he was in "complete shock" and had no explanation for his son's actions.

Alexis was in the Navy from 2007 to January of 2011, which brought him to the Naval Air Station Joint Reserve Base in Fort Worth. He worked as an aviation electrician's mate, petty officer 3rd class, in the Navy Reserve's Fleet Logistics Support Squadron 46, according to Navy records.

The precise nature of his discharge was not immediately available. The Washington Post reported he received a general discharge. Friends said Alexis wanted out because he did not like his work hours or his pay, the Fort Worth Star-Telegram reported. Since then, he had worked for defense contractors, sometimes upgrading computer system for Navy and Marine Corps installations. He occasionally worked as a waiter and delivery person for a Thai restaurant owned by friends. He had moved to Washington recently.

Meditated twice a week

While in Fort Worth, Alexis became friends with many in the local Thai community in the suburb of White Settlement and could be seen regularly at the Wat Busayadhammavanaram Meditation Center, where he went to meditate twice a week. But he still seemed so tightly wound that at least one worker there sought to avoid him, the Los Angeles Times reported.

"He would help people if they came in carrying heavy things," J. Sirun, an assistant to the monks at the Buddhist center, told the newspaper. "From the outside, he was a quiet person. But on the inside, I think he was very aggressive. He did not like to be close with anybody, like a soldier who has been at war."

But Sirun emphasized that he had no reason to believe that his troubles would lead to any sort of explosion.

"I didn't think he could be this violent," Sirun said. "I would not have been surprised to hear he had committed suicide. But I didn't think he could commit murder."

Another temple-goer, Somsak Srisan, told the Times that he rented Alexis a two-bedroom white bungalow behind the temple, and that he never missed a rent payment or caused a problem. Srisan said Alexis had moved out of the house at least several months ago, although he wasn't sure if he had left the Fort Worth area. Srisan said he doesn't know why Alexis left his contractor job at the base. They spoke about it only briefly once, he said.

Friend Kristi Suthamtewakul, whose restaurant Happy Thai Bowl was a gathering spot, told the Houston Chronicle that Alexis had not been happy recently and complained of problems getting government benefits. When she last saw him about two months ago, he seemed defeated.

"He wanted to move out of the country," Suthamtewakul said. "He acted like he was tired of America."

Tired, perhaps, but not violently angry. Nothing that would even hint at the carnage he inflicted Monday, when he carried several weapons into Washington's Navy Yard and opened fire in a cafeteria.

"He was not like that," she said. "There is no way I could have seen this coming. None of us could."

Likewise, other friends were stunned. He seemed like a normal, friendly guy, albeit somewhat reserved, they said. He drank Heineken and socialized with the rest of the group, Mike Ritrovato told the Chronicle. One thing did give Ritrovato pause on Monday.

Shooter video games

"If he had anything (odd) about him, it is that he was a 35-year-old man playing video games," Ritrovato said. "That is the first thing that came to my mind."

When others would gather to watch a football game, Alexis would drift back to his bedroom and play single-shooter video games with online friends. Ritrovato said he treated Alexis like a brother, just like the other regulars at Happy Bowl Thai, whose owners became a surrogate family of sorts. But his online friends were a mystery.

"He took it so seriously in there," Ritrovato said.

Ritrovato admitted he doesn't know what connection the games could make, or if they are relevant.

"I don't know why I am making that connection, but I am trying to make sense of this," Ritrovato said. "My friend just shot 12 people and I just found out he was the only one who did the shooting. Something set him off, and I really don't know what could have done it."

Whatever grievance ate away at him, friends are at a loss to understand. He didn't carry on openly about his problems. And he was a serious Buddhist, if not an obvious one. They grieved his loss Monday, at the same time offering no sympathy for his actions.